import java.sql.*;
import java.util.*;

/**
 * Read-only: 同一个归属 id（talent_id / merchant_id）在两个库里各有多少行、差在哪些表。
 * 用于两库合并后核对「某个账号的数据是不是全在」，以及定位主键撞车影响的表。
 */
public class TenantDataDiff {
    public static void main(String[] args) throws Exception {
        String column = args[0];
        long id = Long.parseLong(args[1]);
        String left = args[2];
        String right = args[3];
        try (Connection a = DriverManager.getConnection(left, "root", "123456");
             Connection b = DriverManager.getConnection(right, "root", "123456")) {
            System.out.println("=== " + column + " = " + id);
            System.out.println("左 " + one(a, "select concat(@@hostname, '/', database())"));
            System.out.println("右 " + one(b, "select concat(@@hostname, '/', database())"));
            System.out.println();
            System.out.format("%-46s %8s %8s %8s%n", "表", "左", "右", "差");
            for (String table : referencingTables(a, column)) {
                if (!exists(b, table)) {
                    System.out.format("%-46s %8s %8s %8s%n", table, count(a, table, column, id), "-", "右库无此表");
                    continue;
                }
                long leftCount = count(a, table, column, id);
                long rightCount = count(b, table, column, id);
                if (leftCount == 0 && rightCount == 0) continue;
                System.out.format("%-46s %8d %8d %8d%s%n", table, leftCount, rightCount, leftCount - rightCount,
                        leftCount == rightCount ? "" : "   <-- 不一致");
            }
        }
    }

    private static List<String> referencingTables(Connection connection, String column) throws SQLException {
        List<String> tables = new ArrayList<>();
        try (PreparedStatement statement = connection.prepareStatement(
                "select table_name from information_schema.columns where table_schema = database() and column_name = ? order by table_name")) {
            statement.setString(1, column);
            try (ResultSet rows = statement.executeQuery()) {
                while (rows.next()) tables.add(rows.getString(1));
            }
        }
        return tables;
    }

    private static boolean exists(Connection connection, String table) throws SQLException {
        try (PreparedStatement statement = connection.prepareStatement(
                "select count(*) from information_schema.tables where table_schema = database() and table_name = ?")) {
            statement.setString(1, table);
            try (ResultSet rows = statement.executeQuery()) {
                return rows.next() && rows.getLong(1) > 0;
            }
        }
    }

    private static long count(Connection connection, String table, String column, long id) throws SQLException {
        // 列名与表名都来自 information_schema，不是外部输入。
        try (Statement statement = connection.createStatement();
             ResultSet rows = statement.executeQuery("select count(*) from `" + table + "` where `" + column + "` = " + id)) {
            return rows.next() ? rows.getLong(1) : 0;
        }
    }

    private static String one(Connection connection, String sql) throws SQLException {
        try (Statement statement = connection.createStatement(); ResultSet rows = statement.executeQuery(sql)) {
            return rows.next() ? rows.getString(1) : "";
        }
    }
}